Whether it's two screens or one is immaterial, like you say. The 2DS is a single screen with a plastic hider.

However, the functionality of displaying two images at once is there to stay, and you can be the U's gamepad functionality will be integrated in the home console successor at least as an accessory (like the motion+ is to the U).

I doubt it. It's not 2004 anymore. 

There's a reason why most (sane) display setups only have a person look at one central display ... because humans aren't adapted to look at multiple displays at the same time. It's pointless. It's also one of the reasons the Wii U is a giant flop -- no Nintendo, it's not that people don't "get" the idea, it's that people recoginize that it's a pretty freaking stupid one. I remember walking past a Wii U kiosk and hearing a girl exclaim to her boyfriend "what screen am I supposed to look at? This is dumb". 

Dual screens made sense in 2004, and Nintendo's been bound to it because of the success of the DS, but they're now liberated to use more modern display setups because the 3DS/Wii U are not having the success they would have liked. Gimme one big display for my Mario level to have its art work shine instead of one smaller screen for that and one entire half screen wasted on a pointless "press here for flower power up!".

I honestly doubt it. They have made use of dual screens and from a gaming perspective it makes more sense. It doesn't have to be two separate screens, like you say, but it could be a tablet display that displays two distinct images at a time.

Either way it doesn't matter because I see the next systems being completely interoperable not only from a platform perspective, but also from an input perspective (compatible with a variety of configurations).

1 reason:

For some games, you don't want to hide the action with your hands. It's more adequate to use a separate display for the touch action.

Also, keep in mind the stylus has certain advantages that no iOS device makes use of, and only a rare exception of Android devices do (Samsung Galaxy Note).

It was an example. What I meant to say is that the Android and iOS apps are not designed for stylus use, and so don't optimise for it. The DS was optimized for gaming and stylus use. That ended in the DS bottom and upper screens.

The advantage I mentioned remains. No screen cluttering with your hands.

As I said though, I see Nintendo implementing a uniformist approach, which would allow for touch as well as stylus as well as dual-screen or single-screen gaming (like 3D World's touch capabilities on off-tv play).

Iwata on integrating handheld/console teams, next system will “absorb the Wii U architecture adequately”, more

Satoru Iwata delivered some incredibly insightful comments as to what Nintendo has planned for its future hardware during an investor briefing Q&A last week.

As many of you know, Nintendo combined its console and handheld teams in 2013. Thanks to “vast technological advances, it became possible to achieve a fair degree of architectural integration.”

Iwata says that the integration of the two teams can help overcome some technical difficulties. He mentioned, as an example, that it currently takes “a huge amount of effort” to port Wii games to 3DS, and 3DS titles to Wii U. “If the transition of software from platform to platform can be made simpler, this will help solve the problem of game shortages in the launch periods of new platforms,” he said.

Integrating the console and handheld teams will also allow Nintendo to avoid situations in which it previously “ended up developing a system that was completely different from its predecessor.” Aside from the transition from GameCube to Wii, “all the other systems required ground-up effort.”

Iwata left a tease as for what’s to come, stating:

In this perspective, while we are only going to be able to start this with the next system, it will become important for us to accurately take advantage of what we have done with the Wii U architecture. It of course does not mean that we are going to use exactly the same architecture as Wii U, but we are going to create a system that can absorb the Wii U architecture adequately. When this happens, home consoles and handheld devices will no longer be completely different, and they will become like brothers in a family of systems.

Be sure to head past the break for Iwata’s comments in full, as there’s quite a bit more he shared that would be silly to summarize further.

Last year Nintendo reorganized its R&D divisions and integrated the handheld device and home console development teams into one division under Mr. Takeda. Previously, our handheld video game devices and home video game consoles had to be developed separately as the technological requirements of each system, whether it was battery-powered or connected to a power supply, differed greatly, leading to completely different architectures and, hence, divergent methods of software development. However, because of vast technological advances, it became possible to achieve a fair degree of architectural integration. We discussed this point, and we ultimately concluded that it was the right time to integrate the two teams.

For example, currently it requires a huge amount of effort to port Wii software to Nintendo 3DS because not only their resolutions but also the methods of software development are entirely different. The same thing happens when we try to port Nintendo 3DS software to Wii U. If the transition of software from platform to platform can be made simpler, this will help solve the problem of game shortages in the launch periods of new platforms. Also, as technological advances took place at such a dramatic rate, and we were forced to choose the best technologies for video games under cost restrictions, each time we developed a new platform, we always ended up developing a system that was completely different from its predecessor. The only exception was when we went from Nintendo GameCube to Wii. Though the controller changed completely, the actual computer and graphics chips were developed very smoothly as they were very similar to those of Nintendo GameCube, but all the other systems required ground-up effort. However, I think that we no longer need this kind of effort under the current circumstances. In this perspective, while we are only going to be able to start this with the next system, it will become important for us to accurately take advantage of what we have done with the Wii U architecture. It of course does not mean that we are going to use exactly the same architecture as Wii U, but we are going to create a system that can absorb the Wii U architecture adequately. When this happens, home consoles and handheld devices will no longer be completely different, and they will become like brothers in a family of systems.

Still, I am not sure if the form factor (the size and configuration of the hardware) will be integrated. In contrast, the number of form factors might increase. Currently, we can only provide two form factors because if we had three or four different architectures, we would face serious shortages of software on every platform. To cite a specific case, Apple is able to release smart devices with various form factors one after another because there is one way of programming adopted by all platforms. Apple has a common platform called iOS. Another example is Android. Though there are various models, Android does not face software shortages because there is one common way of programming on the Android platform that works with various models. The point is, Nintendo platforms should be like those two examples. Whether we will ultimately need just one device will be determined by what consumers demand in the future, and that is not something we know at the moment. However, we are hoping to change and correct the situation in which we develop games for different platforms individually and sometimes disappoint consumers with game shortages as we attempt to move from one platform to another, and we believe that we will be able to deliver tangible results in the future.

Source: http://nintendoeverything.com/iwata-on-integrating-handheldconsole-teams-next-system-will-absorb-the-wii-u-architecture-adequately-more/

As I said, Nintendo is not apple, they make dedicated game consoles. The DS is the result of usability tests they spent money designing. If they see use for it they will keep it, if not they will not. End of story.

Bottom line, Nintendo imho will make their next platforms open to many options, much like the U is today. That is our pattern.

I honestly don't get what this has to do with anything :P What I meant about the U is that it gives players options (play with mote, play on tv, play on screen, etc)